A physical layer secure wireless communication scheme for high speed railway

The high speed railway wireless communication system is much different from public wireless communication system, because the service is train control messages, which is closely related to the safety of train transportation. Thus it is much demanding to the security and reliability. To guarantee the train control messages delivery security, secrecy capacity and outage probability at the high speed railway scenario under single-stream beamforming are analyzed and show that the security requirements can not been satisfied. Thus a physical layer secure wireless communications scheme under beamforming with artificial noise is proposed for high speed railway. In this scheme, artificial noise is used in the null space of the main channel only to degrade the eavesdropper´s channel. Simulation results illustrate the proposed scheme decreases the outage probability under a certain secrecy capacity demand, and meets the secure communication requirements.